Power operated wrench with two-speed drive



July 28, 1964 J. 5. RODGERS 3,142,210

POWER OPERATED WRENCH WITH TWO-SPEED DRIVE Filed June 22, 1962 5Sheets-Sheet 1 32 F1 5'. l 40 I 206 ms E 34 l I 4 96 20o INVENTOR. fins:.5. 200052:

flrramvars July 28, 1964 J. S. RODGERS POWER OPERATED WRENCH WITHTWO-SPEED DRIVE Filed June 22, 1962 5 Sheets-Sheet 2 July 28, 1964 J. s.RODGERS 3,142,210

POWER OPERATED WRENCH WITH TWO-SPEED DRIVE Filed June 22, 1962 5Sheets-Sheet 3 INVENTOR. Jhmss S. Rona-ks 236 flrromvar:

July 28, 1964 t J. 5. RODGERS 3,142,210

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ed S te Paten 3,142,210 POWER OPERATED WRENCH WITH TWO-SPEED DRIVE JamesS. Rodgers, Adams Run, S.C., assignor to Rodgers Hydraulic,Incorporated, Minneapolis, Minn., a corporation of Minnesota Filed June22, 1962, Ser. No. 204,565 2 Claims. (Cl. 8157) The present inventionrelates to wrenches and more particularly to power operated wrenches ofthe type supported for movement relative to a workpiece for performingwork in different areas of the workpiece. The invention has particularutility in the assembly and repair of tractor treads.

In the assembly and disassembly of various articles of manufacture suchas the treads of a tractor, it is a common practice to employ a poweroperated wrench such as an impact wrench. Some of these wrenches must belifted and moved by hand from one bolt to the next as the work proceeds.Carrying such a wrench by hand can I.

While the invention has general application, it is particularly welladapted for the removal and replacement of the grouser plates of tractortread. Due to the abrasive nature of the soil in which track vehiclesfrequently operate, various parts of the tread rapidly become worn andtherefore require relatively frequent replacement or resetting. Therepair operation is begun by removing the tractor treads from thevehicle. The grouser plates are removed and the pins and bushings arethen removed from the rails through the use of a track press of thegeneral type described in the copending application of Vernon K. Quarveand John L. Rodgers, Jr., Serial No. 716,711, filed February 21, 1958,for Track Press, and assigned to the same assignee as the presentapplication.

Among the problems involved in the repair of tractor treads are thefollowing. The bolts which secure the grouser plates to the rails areoften bent or misshapen and frequently are frozen or rusted in place.The wrench must therefore be relatively powerful in order to provide thetorque required to loosen the bolts. At the same time the wrench must bereadily adapted for movement from one point on the tread to another.

Moreover, operation of the wrench should not damage the bolts or thewrench socket either while the bolts are being applied or while they arebeing loosened. In order to reduce the time required for tightening andloosening the bolts, it is desirable to provide greater torque atreduced speed for initially loosening the bolt and an increasedoperating speed for final removal of the bolt.

Accordingly it is one object of the present invention to provide animproved power operated wrench with a support for positioning the wrenchabove a workpiece and including a means for allowing the wrench socketto be moved on a path extending normal to the workpiece as well aslaterally with respect to the workpiece.

It is another important object of the present invention to provide animproved power operated wrench including a supporting framework, awrench drive head mounted thereon with a socket carrying member at thelower end of the drive head and a means for raising and lowering thesocket carrying member relative to the 3,142,210 Patented July. 28,1964.

wrench drive head so as to enable the socket to be readily shifted fromone bolt to the next.

It is yet another object of the present invention to provide an improvedpower operated wrench assembly including a means for providing hightorque for breaking the bolts loose and greater rotational speeds forfinal removal of the bolts.

It is yet another object of the present invention to provide an improvedpower operated wrench having a drive motor, a wrench drive headconnected for transverse movement with respect to the motor and areversing transmission connected between the drive motor and the wrenchdrive head.

It is yet another object of the present invention to provide an improvedpower operated wrench adapted to readily remove rusted or otherwisetightly retained bolts with little tendency to damage either the boltsor the wrench socket.

It is still another object of the present invention to provide animproved power operated wrench which can be moved longitudinally of theworkpiece and will have no tendency to bind on the supporting rails.

It is yet another object of the present invention to provide an improvedpower operated wrench including a supporting framework with a drivemotor mounted thereon, a wrench drive head pivotally mounted upon theframework for swinging movement about a vertical axis and a couplingmeans connecting the motor to the drive head regardless of the angularposition of the drive head with respect to the framework.

These and other more detailed and specific objects will be disclosed inthe course of the following specification, reference being had to theaccompanying drawings, in which FIG. 1 is a side elevational view of anapparatus embodying the present invention.

FIG. 2 is an end elevational view taken on line 22 of FIG. 1.

FIG. 3 is a plan view of the apparatus of FIG. 1.

FIG. 4 is a partial vertical longitudinal sectional view taken on line4-4 of FIG. 2.

FIG. 5 is a partial sectional view taken on line 5-5 of FIG. 3.

FIG. 6 is a partial transverse vertical sectional view taken on line 66of FIG. 4.

FIG. 7 is a partial perspective view of the outward portion of theoperators control handle.

FIG. 8 is a partial elevational view taken on line 83 of FIG. 3.

FIG. 9 is a combined electrical and hydraulic schematic diagram for theapparatus.

Referring now to the drawings and particularly FIGS. 1, 2 and 3 whichillustrate by way of example a preferred form of the present invention,there is shown a power operated wrench including a supporting frameworkor carriage indicated generally at 10. The supporting framework 10includes four downwardly extending legs 12, one such leg being providedat each corner of the framework 10. The framework 10 is provided with aplurality of transversely extending braces 14, one of which can be seenin FIG. 2. Other braces and cross members can be placed where necessaryto provide a requisite strength as will be apparent to those skilled inthe art.

At the upper ends of the legs 12 there is provided a horizontallydisposed metal covering sheet 16. Sheet 16 bends downwardly along eachside edge 18 and 20. Below the sheet 16 is provided a hydraulic fluidstorage reservoir 22 into which hydraulic fluid can be introducedthrough suitable covered filling spouts 24 and 26. A pair of laterallyspaced apart longitudinally extending rails 27 project downwardly fromthe carriage 10. The position of each of rails 27 is laterallyadjustable so that the spacing therebetween can be made to fitworkpieces of different sizes, thereby preventing the torque produced bythe wrench from twisting the workpiece relative to the carriage 10.

At the forward and rearward ends of the carriage 10 and extendingupwardly from the covering sheet 16 are provided four spaced apartvertically positioned braces 28. The lower ends of braces 28 are rigidlysecured to the carriage 10 adjacent the forward and rearward edges ofthe covering sheet 16. A support plate 30 is pivotally secured at 30 tothe upper ends of braces 28 on one side of the apparatus to provide adrive belt tension adjustment. Suitable covering sheets 31 are providedfor enclosing a speed changing and reversing transmission as describedhereinbelow. Rigidly secured to the upper surface of the support plate30 is a drive motor 32 including an output shaft 34 positioned in ahorizontal plane and extending longitudinally of the apparatus. Currentcan be applied to the motor 32 through a conductor 33 connected to themotor 32 through a start and stop switch assembly 36 and a conduit 38.

A sheave 40 is mounted upon the motor shaft 34 at one end thereof and asimilar sheave 42 of a smaller diameter is mounted upon the opposite endas best seen in FIG. 1. Entrained over the sheaves 40 and 42 andextending downwardly therefrom are a pair of flexible belts 44 and 46respectively. As can be seen in FIG. 4, the belt is entrained also overa sheave 48 positioned below the motor 32 and the belt 46 is entrainedover a sheave 50 of a larger diameter than the sheave 48.

As can be best seen in FIG. 4, the apparatus is provided with a clutchand speed changing mechanism indicated generally at 52. The speedchanging mechanism 52 includes a clutch shaft 54 mounted for rotation ona horizontal axis and supported at each end upon hearing blocks 56 and58. The bearing block 56 is suitably connected to a support member 60while the bearing block 58 is suitably supported upon the rearward wallof a reversing transmission 62. A suitable friction reducing bearing canbe provided at 64 within bearing block 56.

Rigidly secured to the shaft 54 are a pair of axially spaced apartradially extending clutch plates 66 and 68. Operatively associated witheach of the clutch plates are a pair of clutch discs 70, 72, 74 and 76respectively. Each of the clutch discs is provided with an integralclutch sleeve designated at 78, 80, 82 and 84 respectively. The sleevesare rotatably mounted upon the clutch shaft 54 by means of suitablesealed bearings 86 which do not require periodic lubrication and thusprevent lubricant from coming in contact with the clutch frictionsurfaces. The bearings 86 of the sleeves 80 and 82 are slidably mountedupon the clutch shaft 54 thereby enabling each of the clutch discs 72and 74 and the associated sleeves 80 and 82 to slide axially of theclutch shaft 54 a limited distance.

The outer ends of the adjacent clutch discs 70 through 76 are connectedby means of bolts 90 which extend parallel to the axis of the shaft 54through suitable circumferentially spaced apart aligned openings in thesev eral discs. The outer ends of each bolt 90 are provided withsuitable connecting means such as a nut 92. The bolt 90 functions as ameans for preventing relatively rotational movement between theassociated clutch disc and also serves to limit the extent to which theassociated pairs of clutch discs can be separated from each other. Theydo not, however, limit the distance that the clutch discs of each paircan move toward each other. Suitable resilient members such as springs93 are mounted between the associated clutch discs for the purpose ofurging the associated discs apart.

Within the outermost ends of the sleeves 78 and 84 are provided suitablebearings such as roller bearings 94 and 96 for reducing friction betweenthe clutch shaft 54 and the sleeves. The sheaves 48 and 50 are mountedrigidly upon the outward extensions of sleeves 78 and 84 respectively.Other friction reducing bearings can be provided where necessary on theshaft 54 as will be apparent to those skilled in the art.

At the approximate center of the shaft 54 is rotatably mounted a clutchoperating collar 100. The clutch operating collar 100 is pivotallymounted by means of a pivot 102 upon a clutch operating lever 104. Theuppermost end of the lever 104 is pivotally mounted at 106 upon asuitable mounting block 108 rigidly secured to the mounting plate 30.Abutting against either side of collar 100 are a pair of thrust bearings110 and 112. Positioned between the thrust bearings 110 and 112 and theinnermost end of the sleeves 80 and 82 are provided suitable spacers 114and 116 respectively for transmitting the thrust exerted by theoperating lever 104 to the clutch discs 72 and 74.

The lower end of the clutch operating lever 104 is pivotally connectedat 118 to the output shaft 120 of a clutch operating actuator orcylinder 122. The cylinder 122 is in turn pivotally connected at 124 toa suitable bracket member 126 rigidly afiixed upon the carriage 10. Theactuator 122 can be operated either by means of compressed air orhydraulic fluid but preferably by means of the latter. Suitablyconnected to the actuator 122 are provided a pair of fluid supply lines128 and 130.

As best seen in FIGS. 4 and 6, at the forward end of the clutch shaft 54is provided a reversing means or transmission 62 including a gear casinghaving side walls 138, a forward wall 139 and a rear wall 140. To theforward end of the shaft 54 within the casing of the reversingtransmission 62 is rigidly secured a pinion gear 142. R0- tatablymounted upon the shaft 54 between the gear 142 and the rear wall is agear carried member 144. The carrier member 144 has rotatably mountedthereon a pair of transversely spaced apart gears 146 and 148. Gear 148is positioned in driving engagement with gear 142 and the gear 146 ismounted in driving engagement with the gear 148 but out of engagementwith the gear 142.

A gear 150 is rotatably mounted at the upper end of the reversingtransmission upon a shaft 152. When the gear carrier 144 is pivotedabout the clutch shaft 54 in a counterclockwise direction to theposition shown in FIG. 6, the gear 148 will be placed in drivingengagement with a gear 150. When the gear carrier 144 is pivoted in aclockwise direction, as viewed in FIG. 6, the gear 148 will bedisengaged from the gear 142 and the gear 146 will become engaged withthe gear 150 thereby reversing the direction and rotation of the gear142 and the shaft 152. Shaft 152 can be suitably mounted upon frictionreducing bearings 154 and 156 within the forward wall 139 of thetransmission casing. The forward end of the shaft 152 is provided with auniversal joint 158.

Rotatably mounted within the casing of the transmis sion 62 upon abracket 160 is a control arm 162 which extends vertically within thecasing and out through the upper end of the casing at 164. The outer endof the control arm 162 has suitably secured to it a control handle 166as can be seen in FIGS. 1, 3 and 4. The lower end of the control arm 162is provided with a forwardly curved portion 168 which projects into arecess 170 at the upper end of the gear carrier 144. It will thus beapparent that when an operator moves the control handle 166 and controllever 162 in a clockwise direction, as viewed in FIG. 3, the gearcarrier 144 will pivot in a counterclockwise direction, as seen in FIG.6, causing the gear 148 to become engaged with the gear 150. Uponreverse movement of the control handle 166, the gear 146 will engage thegear 150.

Pivotally mounted at the upper end of the carriage 10 and extendingforwardly therefrom is a wrench drive head indicated generally at 175.The wrench drive head is mounted upon a pair of vertically spaced apartbracket members 180 and 182 which extend forwardly from the forward wallof the transmission 62.

The drive head includes a swing base member 183 provided with a pair ofvertically spaced apart rearwardly extending projections 188 at itsupper end and a pair of vertically spaced apart rearwardly extendingprojections 190 at the lower end thereof. Projections 188 extend overthe top and bottom of the bracket 180 and are secured thereto by meansof a pivot pin 184. The members 198 extend around the bracket 182 andsecured thereto by a pivot pin 186.

Extending forwardly from the swing base member 183 are a pair ofhorizontally disposed parallel and transversely spaced apart supportmembers such as rods 192 and 194. Mounted upon the rods 192 and 194 is agear casing 196 including an upper Wall 198, side walls 200 and a basemember 202 having a pair of parallel transversely spaced apart openingswithin which the rods 192 and 194 are positioned as best seen in FIGS. 2and 5.

The side wall 200 of the casing 196 is bored at 204 to receive a driveshaft 206 which extends forwardly from the universal joint 158. The endof the drive shaft 206 within the gear casing 196 has secured to it abevel pinion gear 208. The gear 208 is positioned in engagement with aring gear 210 rigidly secured to a vertically disposed wrench outputshaft 212.

The upper end of the shaft 212 has rigidly secured to it at 214 a shaft216 which projects through an upper wall 198 of the gear casing. To theupper end of the shaft 216 is rigidly secured a handwheel 220 to enablethe operator to manually adjust the position of the wrench socket forplacement upon a bolt before power is applied to the wrench. The shaft212 can be suitably rotatably mounted upon friction reducing bearings222 and 224.

Upon the lower end of the base member 202 is secured a fitting 226suitably bored at 228 thereby allowing the lower end of the shaft 212 toproject outwardly through the lower end thereof. The extreme lower endof the shaft 212 is provided with a square cross-sectional configuration230. Upon the square portion the shaft 230 is slidably mounted a socketsupporting member 232. The member 232 is provided with a bore of asquare crosssectional shape so as to allow sliding movement between theshaft 212 and the member 232 but, at the same time, preventing rotationbetween these members.

Upon the lower end of the member 232 there is rotatably mounted a sleeve234 to which a bracket 238 is secured by means of a pair of coaxialhorizontally spaced apart pivot pins 236. The pins 236 also pivotallysecure the bracket 238 to a pair of parallel horizontally spaced apartlever arms 240. At one end of the lever arms 248 is secured a generallydiagonally extending pair of lever arms 244. The upper ends of thesearms are pivotally secured at 246 to the lower end of the fitting 226.

Secured to the lower end of the fitting 226 is a bracket 248 forrotation relative thereto about a vertical axis and connected betweenthe brackets 248 and 238 are a pair of vertically extending parallel andtransversely spaced apart resilient members such as springs 251 and 252.The springs 250 and 252 urge the bracket 238, collar 234 and theassociated members upwardly onto the portion 230 of the shaft 212thereby yieldably biasing these parts upwardly and away from theworkpiece. Upon the lower portion 254 of the socket support member 232is detachably secured a suitable wrench socket 256 of any required size.

As best shown in FIGS. 1, 2, 3 and 7, at the outer end of the lever arm240 is rigidly secured a switch enclosure 260 within which is mounted athree position selector switch 262. Extending outwardly from the outerend of the enclosure 260 is a tube 264 within which is rotatably mountedan elongate control handle 266. The inner end of the control handle 266is operatively connected to the switch 262. By twisting the controlhandle 266 in one direction, the wrench output shaft 212 can be made torun at slow speed and by twisting the control handle 266 in the oppositedirection, the output shaft can be made to run at a faster speed as willbe described more fully hereinbelow. When the control handle 266 isturned to an intermediate position, neither of the clutches will beengaged and the wrench output shaft 212 will stop turning.

As can be best seen in FIGS. 1, 2, 3 and 8, at the lower end of thecarriage 10 is rigidly secured a pair of laterally spaced aparthorizontally disposed frame members 280 and 282. Rotatably mounted atopposite ends of the respective frame members 280 and 282 are a pair ofwheels 284, one pair being provided on each of the members 280 and 282.Since each side of the apparatus is provided with identical wheels andWheel operating means, only the wheel mechanism on one side of theapparatus will be described in detail.

Each of the wheels 284 has rigidly secured to it a sprocket 286. Each ofthe wheels 284, at the forward end of the carriage 10, are provided witha second sprocket 288 positioned adjacent the sprocket 286. Spacedforwardly of each of the front wheels 284 is a handwheel 290. Eachhandwheel 290 is rotatably mounted upon the respective frame members 280and 282 for rotation on a horizontal axis upon a support shaft 292.Rigidly secured to each shaft 292 is a sprocket 294. Entrained betweenthe sprockets 294 and 288 on each side of the carriage 10 is a drivechain 296 and entrained over the sprockets 286 on each side of thecarriage is a drive chain 298.

To the extreme forward and rearward ends of the frame members 280 and282 are rigidly secured a pair of mounting blocks 300. Each of themounting blocks 300 has mounted at the upper end thereof for rotationabout a vertical axis, an anti-bind wheel 302 positioned in tangentialabutting relationship with the vertical wall of one of a pair ofsupporting rails 304 as can be seen in FIGS. 1, 3 and 8. The wheels 284are adapted to rest upon the lower wall of the supporting rail 384 tothereby support the carriage 10 for longitudinal movement along therails. The rails 304 are suitably supported above the floor or othersurface by means of a plurality of supporting legs 306. Rotatablymounted between the rails 304 are a plurality of horizontally disposedtransversely extending rollers 398. Thus when the apparatus is to beused, a workpiece, such as a section of tractor track 310 as shown inFIG. 1, can be moved over the rollers 308 to the desired position belowthe wrench drive head 175. As the repair operation continues, thecarriage 10 can be moved along the rails 304 longitudinally of theworkpiece 310 by turning either of the handwheels 290.

The electrical hydraulic system can be best understood by reference toFIG. 9. In FIG. 9 there is shown a power supply line 318 which can beconnected to a suitable source of current (not shown). The conductors318 are connected through a knife switch 320 to the drive motor 32. Eachof the conductors 318 is provided with a solenoid operated switch 322 ofany suitable known construction. In series with the switches 322 areprovided suitable fuses 324. Connected across the conductors 318 areconductors 326 and 328. Connected in series between the lines 326 and328 is a stop switch 330, a starting switch 332 and a relay 334. Inseries with the switch 332 is a holding coil 335 of conventional knownconstruction. Additional fuses are provided at 338, 340 and 342. Thearmature of relay 334 is connected to the switches 322 by a connectingmember 337. Wired to the conductor 326 is a conductor 343 leading to oneterminal of each of solenoids 344 and 346. Solenoids 344 and 346 areboth operatively connected to a four-way hydraulic valve 348 of knownconstruction. The other terminals of solenoids 344 and 346 are coupledby conductors 350 and 352 respectively through the three positionselector switch 262 to the conductor 328.

The hydraulic system includes a suitable hydraulic pump 35 coupled tothe shaft of the motor 32 and connected between an inlet line 360leading to the storage reservoir 22 and a line 362 leading to the valve348. The outlet of valve 348 is connected through a line 366 to thereservoir 7 22. The line 128 communicates between one end of theactuator 122 and the valve 348 while the line 130 communicates betweenthe valve 348 and the other end of actuator 122. Communicating with thepump outlet line 362, as seen in FIGS. 1 and 9, is a pressure gauge 368and a pressure control valve 370 of a suitable known construction. Valve370 will permit an operator to control the hydraulic pressure in line362 and in turn the pressure exerted by the actuator 122 upon the clutchdiscs. Lower pressures can be employed when bolts of a relatively smallsize are being tightened so as to allow the clutches to slip and thusavoid breakage of the bolts.

Operation While the apparatus according to my invention can be used toperform work on different types of workpieces, it will be described withparticular reference to the assembly and repair of tractor treads.

When the apparatus is to be used, the tractor tread 310 is placed on therollers 308 and moved to the position illustrated in FIG. 1 with thebolts which are to be removed positioned beneath the socket 256 of thewrench. After a bolt has been removed, the carriage 10 of the apparatuscan be moved longitudinally of the workpiece by turning either of thehandwheels 290 to quickly and efliciently position the socket 256 inposition to receive the next bolt. At the same time the wrench drivehead 175 can be swung about the pivots 184 and 186 to the left or rightas required. When the wrench socket 256 is positioned directly over abolt on the workpiece 310, the handwheel 220 can be turned manually toplace the socket 256 in the position required to exactly fit over thebolt. The handle 264 can then be lowered manually against the retentionof springs 250 and 252 to place the socket 256 over the head of a bolt.

The motor 32 can be started by closing switches 320 and 322. If the boltis to be loosened, the reversing transmission control lever 166 ispivoted in the direction required to cause the socket 256 to rotate in acounterclockwise direction as seen in FIG. 3. The portion 266 of thecontrol handle 264 is then twisted in a first direction so as to actuatesolenoid 344. This will draw the plunger of valve 348 to the left (FIG.9) and cause the output shaft 120 of actuator 122 to move toward theright as seen in FIG. 4, thereby engaging the clutch discs 74 and 76with a clutch plate 78. Under these conditions, the clutch plates 70 and72 will be released from engagement with the plates 76 and with themotor 32 in operation, power will be transmitted through belt 46 tosheave 50 and in turn to the clutch shaft 54 through gear 142 and one ofthe gears 146 or 148 to the gear 150. Rotation of gear 150 will in turnrotate the shaft 152, universal joint 158 and drive shaft 206. The driveshaft 206 will in turn rotate the pinion gear 208 and ring 210 therebyturning the wrench output shaft 212 and the socket member 232.

After the bolt has been initially loosened, lever 266 can be twisted inthe opposite direction thereby actuating the selector switch 262 tosupply current to the solenoid 346 rather than solenoid 34-4. This willcause the output shaft 120 of actuator 122 to move toward the left asseen in the drawings thereby engaging the clutch discs 70 and 72 withthe clutch plate 66. Under these conditions power will be transmitted tothe shaft 54 through the belt 44 thereby causing the shaft 54 to rotateat a higher speed. As a result, the bolts which have been loosened canbe removed more quickly and efiiciently. The handle 266 can then betwisted to an intermediate position thereby interrupting the current toboth of solenoids 344 and 346. The lever 104 will then move to anintermediate position and both clutch assemblies will be disengaged soas to halt rotation of the output shaft 212.

The present invention provides a number of important advantages. Thespeed changing assembly as disclosed herein provides an inexpensivemethod of obtaining two driving speeds as contrasted with a gear typetransmission. Furthermore, the change from one speed to another isalmost instantaneous. If it were necessary to release a clutch, shiftgears and then reengage the same clutch, a much slower response would beprovided than in the speed changing assembly according to the presentinvention. Moreover, by providing both high and low speeds at the wrenchsocket, additional power will be provided for breaking loose rustedbolts and, furthermore, slow speed operation has ben found desirable forloosening certain relatively large bolts which have been found tooverheat if turned at relatively high speeds.

Another advantage of the invention derives from the fact that since thebracket 248 and lever arms 240 and 244 can be rotated about a verticalaxis on the fitting 226, the handle 266 can be moved to either side ofthe apparatus so that the bolts may be readily removed by an operatorpositioned on either side of the workpiece. It is also an importantfeature of the invention that the wrench can be operated entirely by asingle control, thereby making it possible for an operator to controlthe wrench operation with one hand and hold the nuts from turning withthe other hand, thus eliminating the requirement for a helper.

Another important feature of the invention is that the socket and itsdriving shaft are maintained perpendicular to the workpiece throughoutoperation. As a result, the relative movement between the socket and thehead of the bolt being worked on will be held to a minimum. Thisprovision has been found to add significantly to the life of the socket.Furthermore, the steady movement of the wrench socket makes it possiblefor the socket to drive bolts which a conventional impact wrench couldnot turn because the jar produced by an impact wrench would cause thesocket to turn on a worn bolthead. It has been found that the steadymovement of the Wrench socket also makes it less diflicult to hold thenuts of the bolts. The sockets, when used with my invention, will lastvery much longer than the sockets of a conventional impact wrench. Ithas been found that it will often require two or more sockets for asingle tractor tread when a conventional impact wrench is employed,whereas in my invention, on the other hand, the sockets appear to lastindefinitely.

The torque control through the regulation of hydraulic pressure on theclutch plates, according to my invention, serves as a means forprotecting small or weakened bolts and, even more important, it assuresthat the bolts will be tightened to the proper degree for the particularsize bolt employed. The regulation of the pressure on the clutch platesas disclosed herein thus enables all of the bolts in a tractor tread tobe tightened to the same torque without depending upon the skill of theoperator, as is commonly done when a conventional impact wrench isemployed. It will, of course, be understood by those skilled in the artthat the bolts must be properly tightened to prevent the grouser platesfrom working loose.

It is understood that suitable modifications may be made in thestructure as disclosed, provided such modifications come within thespirit and scope of the appended claims. Having now therefore fullyillustrated and described my invention, what I claim to be new anddesire to protect by Letters Patent is:

l. A power operated wrench comprising in combination; a supportingframework; a drive motor rigidly mounted upon said supporting framework;a drive head pivotally connected to one end of said framework formovement about a vertical axis with respect to said framework, saiddrive head extending outwardly from said supporting framework; avertically disposed Wrench out put shaft rotatably mounted within saiddrive head, a horizontally disposed shaft in driving engagement withsaid wrench output shaft and rotatably mounted within said wrench drivehead; drive means rotatably mounted upon said framework and operativelyconnected to said drive motor for rotation therewith; a flexiblecoupling means connected between said drive means and said horizontallydisposed shaft; a socket supporting member s1idably mounted upon thelower end of said wrench output shaft; means coupling said socketsupporting member and said wrench output shaft for preventing relativerotational movement therebetween and a control member operativelyconnected between said drive head and said socket supporting member forsliding said socket supporting member axially of said wrench outputshaft.

2. A power operated wrench comprising in combination; a supportingframework, wheel means on said framework for allowing said framework tobe moved longitudinally of a workpiece, drive means operativelyconnected to said wheel means for imparting rotary movement thereto, adrive head pivotally mounted upon said framework for swinging movementabout a vertical axis, said drive head extending outwardly from one endof said framework, a drive motor mounted upon said framework, 2.horizontally disposed clutch shaft mounted upon said framework adjacentsaid drive motor, first and second selectively operable clutchassemblies positioned upon said clutch shaft, first and second drivemeans operatively connected between said drive motor and said first andsecond clutch assemblies respectively, said first clutch assembly beingadapted to engage said clutch shaft with said first drive means and saidsecond clutch assembly being adapted to engage said clutch shaft withsaid second drive means, said first drive means having a speed ratiodifferent from the speed ratio of said second drive means, a reversingtransmission operatively connected to said clutch shaft, a wrench outputshaft rotatably mounted upon said drive head, coupling means connectingsaid wrench output shaft and reversing transmission, said coupling meansincluding a universal joint, an enlarged manually operable memberrigidly connected to said wrench output shaft for positioning saidwrench output shaft with respect to a workpiece, a socket supportingmember slidably mounted upon said wrench output shaft, means couplingsaid wrench output shaft and said socket supporting member forpreventing relative rotational movement therebetween and a control levermeans operatively connected between said wrench drive head and socketsupporting member for sliding said socket supporting member axially ofsaid wrench output shaft.

References Cited in the file of this patent UNITED STATES PATENTS975,042 Jacobs Nov. 8, 1910 1,060,173 Edwards Apr. 29, 1913 1,189,754Trenaman July 4, 1916 1,666,600 Jorden Apr. 17, 1928 1,734,475 DedgeNov. 5, 1929 1,754,978 Buss Apr. 15, 1930 1,807,367 Woolery May 26, 19312,000,221 Dawson May 7, 1935 2,034,740 Brandt Mar. 24, 1936 2,228,589Backes Jan. 14, 1941 2,433,959 Runkle Jan. 6, 1948 2,538,276 ShotfnerJan. 16, 1951 3,017,794 Pouget Jan. 23, 1962 FOREIGN PATENTS 1,152,231France Sept. 2, 1957

1. A POWER OPERATED WRENCH COMPRISING IN COMBINATION; A SUPPORTINGFRAMEWORK; A DRIVE MOTOR RIGIDLY MOUNTED UPON SAID SUPPORTING FRAMEWORK;A DRIVE HEAD PIVOTALLY CONNECTED TO ONE END OF SAID FRAMEWORK FORMOVEMENT ABOUT A VERTICAL AXIS WITH RESPECT TO SAID FRAMEWORK, SAIDDRIVE HEAD EXTENDING OUTWARDLY FROM SAID SUPPORTING FRAMEWORK; AVERTICALLY DISPOSED WRENCH OUTPUT SHAFT ROTATABLY MOUNTED WITHIN SAIDDRIVE HEAD, A HORIZONTALLY DISPOSED SHAFT IN DRIVING ENGAGEMENT WITHSAID WRENCH OUTPUT SHAFT AND ROTATABLY MOUNTED WITHIN SAID WRENCH DRIVEHEAD; DRIVE MEANS ROTATABLY MOUNTED UPON SAID FRAMEWORK AND OPERATIVELYCONNECTED TO SAID DRIVE MOTOR FOR ROTATION THEREWITH; A FLEXIBLECOUPLING MEANS CONNECTED BETWEEN SAID DRIVE MEANS AND SAID HORIZONTALLYDISPOSED SHAFT; A SOCKET SUPPORTING MEMBER SLIDABLY MOUNTED UPON THELOWER END OF SAID WRENCH OUTPUT SHAFT; MEANS COUPLING SAID SOCKETSUPPORTING MEMBER AND SAID WRENCH OUTPUT SHAFT FOR PREVENTING RELATIVEROTATIONAL MOVEMENT THEREBETWEEN AND A CONTROL MEMBER OPERATIVELYCONNECTED BETWEEN SAID DRIVE HEAD AND SAID SOCKET SUPPORTING MEMBER FORSLIDING SAID SOCKET SUPPORTING MEMBER AXIALLY OF SAID WRENCH OUTPUTSHAFT.